Questions about breast animation

[Jonny Long]

This is a really broad question that I feel like requires a lot of personal research from me. I'm not a developer and have no background in animation, but I've experimented with cloth and soft body simulations in Blender. With these simulations, I've never gotten the breast to have a realistic flow during movement. They're unironically like wrinkled bags of sand. I've seen some decent renders over the years and wondered how these animations were done? I'm assuming mostly with key frames and a bit of physics?

Examples would be Umemaro:
I noticed that the breasts were soft bodies that drooped down and tuck themselves under, while not deforming into bags during animation.

...another thing that bothered me is that the physics simulations were using an insane amount of my computer's resources for bad results. I feel like I'm doing something wrong or are simulations generally that intensive to create?

 

[n00bi]

This is a really broad question that I feel like requires a lot of personal research from me. I'm not a developer and have no background in animation, but I've experimented with cloth and soft body simulations in Blender. With these simulations, I've never gotten the breast to have a realistic flow during movement. They're unironically like wrinkled bags of sand. I've seen some decent renders over the years and wondered how these animations were done? I'm assuming mostly with key frames and a bit of physics?

I am not sure about Blender, but using softbody for some simple breast jiggle and some collision is overkill for the most part imo.
You should make something like a vertex map for the areas you want to be affected by the physics.
example.:


I am not sure what the name in Blender would be but this map is not to be confused with a Weight map that is used for the skin.

Once you have done the vertex map you would apply a modifier to the mesh, a jiggle/bounce modifier and have it use the vertex map for where it should do its influence.

Also it can matter how you want to apply it.
What i mean by this.
If you are making the animation from scratch the modifiers and physics should act normally.

But if you try to apply for example a jiggle modifier onto skinned mesh, with a per-existing animation you might run into issues.

Example.
Left: is Daz walk anim exported, just stock walk anim.
Middle: is added a jiggle modifier to the skinned mesh. and you see the awefull result.
Right : is the stock anim converted to Alembic then added the jiggle modifier to.

This example shows it a bit to the extreme.
But depending on what needs to be done this may not always be a issue.
Just saying it can be.



But as said. using jiggle/bounce/collision eg, modifers on a rig with no premade anim should work fine tho.
Some jiggeling on a washing machine randomly moving around .



In C4d you can in fact have multiple vertex maps on the same mesh.
one for collision, one for jiggle etc. i guess Blender can do something like it..

...another thing that bothered me is that the physics simulations were using an insane amount of my computer's resources for bad results. I feel like I'm doing something wrong or are simulations generally that intensive to create?

Using Physics can be heavy on the computer. esp if you have a lot of simulations in the scene.
If Blender allows it. you should make a cache of the simulation types if your working with cloth and other physics at the same time.

And most times there is a trade off with physics.
Make something that is Good Enough vs Spend a shit load of computing time before even starting to render

 

[Jonny Long]

View attachment 4934040

Thanks, that's actually pretty good explanation. It pretty much works the same in Blender.
I imagine this would work great for ripple effect animations. xD

But I'm also wondering about is really complex breast where the breasts fold above the skin.

Or where it only partially caves in on itself because of the direction of the body:

These are not simple wiggle bone animations, the breasts are obviously distorting.
So how do they retain their form so much while being soft bodies?

 

[n00bi]

These are not simple wiggle bone animations, the breasts are obviously distorting.
So how do they retain their form so much while being soft bodies?

I must be carefull not to lead you on a path that is not how its done in Blender as it seams to be your tool.
But there should be parameters you can adjust for this on the modifiers.

Take a note the method i described above is using modifiers and not softbody dynamics.
On my jiggle modifier i have several options.

You can see several tabs. but Object is the most important one.
Here you adjust the strength of the modifier. stiffness. structural (trying to retain its orginal shape) etc
Also you see this Map field. here you can have a vertext map define and fine tune where the areas of influence is.



So what you see in your animation clip above can be done by setting up the modifiers properly and use vertex maps to getbetter results.

There is ofcource the option to use softbody aswell.
And it has way more (vertex)maps that can be used to adjust the dynamics.



I dont know if Blender has this Jiggle modifier.

But what is seen above can be done just using jiggle and some vertex maps and adjusting the strength.

One just have to play around a bit until youre happy.

 

[Jonny Long]

But what is seen above can be done just using jiggle and some vertex maps and adjusting the strength.

That's really good to know, I'm not sure if blender has it by default, but I'll be sure to try out what you suggested.
I tried using a soft body modifier around a cage on the breasts before, it worked kind of but it felt like overkill.
...and if it isn't an option, I can always try another tool. Thanks!

 

[n00bi]

I'm not sure if blender has it by default, but I'll be sure to try out what you suggested.

Google is amazing,
It told me Blender does sadly not have a native jiggle modifier like i have in C4D.
However it can be replicated by several methods. don't ask me how tho.

I see mainly two methods listed.
Using SoftBody with a vertex group. (vertex map in c4d), kind of like what i have described.
or use Geometry Nodes with a vertext group.

I can always try another tool.

There is always Cinema 4D
Blender is an amazing tool, but Cinema 4D’s tool quality and integration are hard to beat in terms of animation / motion design etc. Blender is a better sculpting tool tho.
But this isn't really a quick fix to just swap tools, it takes time to learn new tools and workflow.

Just dont.. dont use Daz for animations involving physics. while its capable of doing some simulations (DForce etc),
its far from as capable as Blender/C4D/Maya etc

 

[MissFortune]

Have you tried Simplicage? Makes breast stuff fairly easy, it's down to settings after that. Also some preset stuff on their Discord that looks pretty good.

 

[drapak12]

I think that even with best software, tools and skills you can animate only small, firm 18y old breasts. Physic animation can (better or worse) simulate skin movement, but tissues - colagen, fat and muscles are too advanced. I've tried many tools/plugins and none of them were good.

I think best solution is still manual adjusting morphs to phantom prop animation.
More tips you can find here:
https://f95zone.to/threads/how-to-get-good-butt-bounce-jiggle-in-daz3d.240998/

This one were made manually without any script, just morphs. Anyway I created several times before I obtained acceptable results and still I see misstakes like crowfeets visible/invisible.

 

[Jonny Long]

Have you tried Simplicage? Makes breast stuff fairly easy, it's down to settings after that. Also some preset stuff on their Discord that looks pretty good.

I have, but I didn't really like the results as much. It was pretty resource heavy personally.

 

[Jonny Long]

I think that even with best software, tools and skills you can animate only small, firm 18y old breasts. Physic animation can (better or worse) simulate skin movement, but tissues - colagen, fat and muscles are too advanced. I've tried many tools/plugins and none of them were good.

I think best solution is still manual adjusting morphs to phantom prop animation.
More tips you can find here:
https://f95zone.to/threads/how-to-get-good-butt-bounce-jiggle-in-daz3d.240998/

This one were made manually without any script, just morphs. Anyway I created several times before I obtained acceptable results and still I see misstakes like crowfeets visible/invisible.

That's pretty good, I'll try a bunch of things.

 

[n00bi]

Physic animation can (better or worse) simulate skin movement, but tissues - colagen, fat and muscles are too advanced. I've tried many tools/plugins and none of them were good.

What do you mean by fat and muscles are too advance?
Fat can be controlled by vertex maps/groups and with the usage of force (Gravity)
One scenario where Breast fat needs more simulation that just pure jiggle/bounce is when the character is laying down on her back.
The breast should be more flat in compared to standing up.
Simple example with one boob more flat laying down,, (wait gif loading)


Fat is way more simple than muscles. just add some jiggle/bounce for the belly/ass etc and you are done for the most part
Muscles would be a skin type on the mesh and is not really a physics thing in itself.
While you can add bounce/jiggle etc to muscles, but rock hard muscles would be way less effected as fat would be.
The problem using a proper muscle system it that it takes a bit time to setup the rig.
And you kind of need to be a doctor knowing muscle anatomy or have medical books with pics for reference to build up a realistic muscle rig

Example pic, with a bit transparency on the skin mat to see the how muscles would behave.



And most of us are interested in good looking feminine girls.
Not beefy looking chads
So is it worth setting up a full body rig with muscles.. meh..

All the major 3d tools (c4d, maya, 3ds max etc) have some sort of muscle system.
seams like a missing feature from blender. i am sure there are workarounds for it tho.

 

[drapak12]

What do you mean by fat and muscles are too advance?
Fat can be controlled by vertex maps/groups and with the usage of force (Gravity)
One scenario where Breast fat needs more simulation that just pure jiggle/bounce is when the character is laying down on her back.
The breast should be more flat in compared to standing up.
Simple example with one boob more flat laying down,, (wait gif loading)

Fat is way more simple than muscles. just add some jiggle/bounce for the belly/ass etc and you are done for the most part
Muscles would be a skin type on the mesh and is not really a physics thing in itself.
While you can add bounce/jiggle etc to muscles, but rock hard muscles would be way less effected as fat would be.
The problem using a proper muscle system it that it takes a bit time to setup the rig.
And you kind of need to be a doctor knowing muscle anatomy or have medical books with pics for reference to build up a realistic muscle rig

Example pic, with a bit transparency on the skin mat to see the how muscles would behave.


And most of us are interested in good looking feminine girls.
Not beefy looking chads
So is it worth setting up a full body rig with muscles.. meh..

All the major 3d tools (c4d, maya, 3ds max etc) have some sort of muscle system.
seams like a missing feature from blender. i am sure there are workarounds for it tho.

It is all true. You can simulate some type of body and some poses, but it is limited.
View attachment 4939125
This one I called "small, firm 18y old breasts". If you check f95 artwork forum you find only few of them and plenty of giga boobs.
Most simulations scripts (not only dforce) consider only surface animation calculating weight, fold, bend/share and jiggle treating it as a cloth in space. Tissues like adipose tissue, connective tissue works like expansion/support of cloth surface and they have their own physic.
Muscle simulation is not important, because tight muscles are hard and not jiggle. Rleaxed muscles behave similar to adipose tissue.
View attachment 4938413
This pose can be calculated like clothes on figure, but instead of cloth you have skin and instead of figure you have biceps.

I'm trying to explain that you can simulate jiggle with tools like dforce engine or other plugins, but is is very limited. It consider only one calcylated variable - skin/surface (muscles shape is not calculated just mophed). You need more then one variable to obtain realistic results.
I've tried to create some asset for daz which contain dforce surface (like your blender) and dforce wind node placed inside body which simulated expansion of tissues. I had some funny results but not good enough to share it.
Anyway I wanted to say that auto jiggle tools work, but manual setting/adjusting morphs takes a lot of time and is difficult but in most "f95" animations gives better results then any automatic calculations.